1. Technical Field
This invention relates to signal processing systems, and more particularly to a system that may estimate and suppress reverberation.
2. Related Art
Sound is susceptible to noise that can corrupt, mask, or otherwise affect clarity, intelligibility, directionality, or other characteristics of the sound. Reflected sound is a common noise source. Reflected sound overlaps the source signal at a sensor such as a microphone with time-delayed versions of the original signal. The overlap, also known as reverberation, sometimes reduces the perceptibility of speech or other sounds.
Reverberation may make sound seem distant or tinny, seem to be emanating from a tunnel or cave, or may otherwise impair the quality or intelligibility of that sound. Reverberation is common in open and closed spaces. Cars, offices, gymnasiums, churches, and other closed spaces may be affected by the echo-like affect of reverberation. Reverberations may also affect open areas near walls, buildings, cliffs, or other structures.
Some prior signal processing systems attempt to reduce reverberation through blind deconvolution. Blind deconvolution attempts to estimate the transfer function of the room, office, or other reverberant signal environment. The sensed signal is applied to an inverse filter to estimate the original signal.
Blind deconvolution attempts to exactly recover the original signal through the determined signal environment transfer function. This process is an extremely complicated and computationally intensive technique. As such, it can be unsuitable for devices such as mobile phones that provide real time response or for devices that may not be able to devote adequate processing resources to the blind deconvolution.
There is a need for a system that estimates and suppresses reverberant signal components.